title: The mitochondrial genome impacts respiration but not fermentation in interspecific Saccharomyces hybrids.
abstract: In eukaryotes, mitochondrial DNA (mtDNA) has high rate of nucleotide substitution leading to different mitochondrial haplotypes called mitotypes. However, the impact of mitochondrial genetic variant on phenotypic variation has been poorly considered in microorganisms because mtDNA encodes very few genes compared to nuclear DNA, and also because mitochondrial inheritance is not uniparental. Here we propose original material to unravel mitotype impact on phenotype: we produced interspecific hybrids between S. cerevisiae and S. uvarum species, using fully homozygous diploid parental strains. For two different interspecific crosses involving different parental strains, we recovered 10 independent hybrids per cross, and allowed mtDNA fixation after around 80 generations. We developed PCR-based markers for the rapid discrimination of S. cerevisiae and S. uvarum mitochondrial DNA. For both crosses, we were able to isolate fully isogenic hybrids at the nuclear level, yet possessing either S. cerevisiae mtDNA (Sc-mtDNA) or S. uvarum mtDNA (Su-mtDNA). Under fermentative conditions, the mitotype has no phenotypic impact on fermentation kinetics and products, which was expected since mtDNA are not necessary for fermentative metabolism. Alternatively, under respiratory conditions, hybrids with Sc-mtDNA have higher population growth performance, associated with higher respiratory rate. Indeed, far from the hypothesis that mtDNA variation is neutral, our work shows that mitochondrial polymorphism can have a strong impact on fitness components and hence on the evolutionary fate of the yeast populations. We hypothesize that under fermentative conditions, hybrids may fix stochastically one or the other mt-DNA, while respiratory environments may increase the probability to fix Sc-mtDNA.
authors.affiliation: Univ. de Bordeaux, ISVV, EA 4577, Unité de recherche CEnologie, Villenave d'Ornon, France ; Bordeaux Sciences Agro, Gradignan, France.
authors.forename: Warren
authors.initials: W
authors.lastname: Albertin
authors.forename: Telma
authors.initials: T
authors.lastname: da Silva
authors.forename: Michel
authors.initials: M
authors.lastname: Rigoulet
authors.forename: Benedicte
authors.initials: B
authors.lastname: Salin
authors.forename: Isabelle
authors.initials: I
authors.lastname: Masneuf-Pomarede
authors.forename: Dominique
authors.initials: D
authors.lastname: de Vienne
authors.forename: Delphine
authors.initials: D
authors.lastname: Sicard
authors.forename: Marina
authors.initials: M
authors.lastname: Bely
authors.forename: Philippe
authors.initials: P
authors.lastname: Marullo
mesh_terms: D000704:Analysis of Variance; D001483:Base Sequence; D016000:Cluster Analysis; D003433:Crosses, Genetic; D017931:DNA Primers / Q000235:genetics; D005285:Fermentation; D005434:Flow Cytometry; D056084:Genetic Fitness / Q000235:genetics*; D005819:Genetic Markers / Q000235:genetics; D054629:Genome, Mitochondrial / Q000235:genetics*; D005838:Genotype; D006824:Hybridization, Genetic / Q000235:genetics*; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D010101:Oxygen Consumption / Q000502:physiology; D010802:Phylogeny; D011157:Population Dynamics; D012119:Respiration / Q000235:genetics*; D012440:Saccharomyces / Q000235:genetics / Q000502:physiology*; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D005819:Genetic Markers